Firstborns are supposed to be conscientious, agreeable — and smarter than their younger siblings, writes Ami Albernaz in the Boston Globe. The youngest in the family is supposed to be free-spirited and outgoing.
However, personality and IQ differences associated with birth order “are so small as to have no practical impact,” according to a University of Illinois study published in the Journal of Research in Personality.
The Illinois study used data on 377,000 U.S. high school students and controlled for factors such as number of siblings, socioeconomic status, family structure, age, and gender.
Among the slight personality differences the researchers found, firstborn children were more conscientious and agreeable, and less sociable and neurotic, than later-born kids. Yet though these differences were statistically significant, they were so small as to be meaningless, the researchers wrote. Firstborns also had slightly higher IQs, but this difference — about one point — was also not enough to be perceptible.
“Parents will often say their firstborn is more responsible,” said Rodica Damian, the study’s co-author. “But unless you have a video camera and can go back to when the firstborn was the age of the second-born or lastborn, you can’t fairly compare. Your personality changes as you age.”
I was the second of four children, but raised as my 15-months-older sister’s twin. People used to ask if we were identical twins, even though she was taller. She also was smarter than me — and not just because she was older. She had more musical and artistic talent. I was the sensible one. It didn’t seem like much at the time, but it’s worked out for me. Growing up trying to compete with my sister was good training too.